Bear

One species, many faces

Brown bears are taxonomically a single species (Ursus arctos) with at least 15 named subspecies. The range of body sizes within the species is enormous:

• Eurasian brown bear — 100–250 kg.
• Grizzly bear (interior North America) — 120–360 kg.
• Kodiak bear (Alaska’s Kodiak Archipelago) — up to 680 kg, the largest land carnivore on Earth (rivalling polar bears).

Diet drives the size differences. Coastal Kodiak bears gorge on salmon and grow huge; interior grizzlies eat mostly plants and small mammals and stay smaller.

Hibernation, technically

Brown bear hibernation isn’t true hibernation in the strict scientific sense (where body temperature drops to near-ambient). Bears enter a state called torpor — heart rate drops from 40 to 8 beats per minute, breathing slows, body temperature drops only a few degrees, and the bear neither eats, drinks, nor excretes for up to 6 months. They lose 25–40% of their body weight during torpor, mostly fat.

Females give birth in the den during torpor, and cubs nurse in the den until spring. The mother’s metabolism handles all this without measurable bone loss or muscle atrophy — a feat that has interested medical researchers for decades.

Smarter than they look

Brown bears solve complex puzzles, use tools (including rocks to scratch their faces), and remember food sources for years. They have spatial memory good enough to navigate to remembered berry patches across hundreds of kilometers. In contests of cognition, brown bears generally outperform domestic dogs and rival great apes on certain tasks.

Not a single bear, several names

The subspecies labels can be confusing:

• “Grizzly” — North American interior brown bears.
• “Kodiak” — Brown bears on Kodiak Island.
• “Eurasian brown bear” — across Eurasia.
• “Himalayan brown bear” — Tibetan Plateau and Himalayas; possibly the basis of yeti legends.
• “Syrian brown bear” — surviving small population in the Caucasus.

All are Ursus arctos; they can interbreed and have done so historically along range boundaries.

Coexistence

Brown bears have an outsized place in human culture — terror, totem, mascot, emblem. The cultural image often outpaces the actual risk: fatal bear attacks on humans are rare (single digits per year in North America). The reverse is far more common; bears are killed by humans through hunting, vehicle strikes, and conflict over livestock and crops at orders of magnitude higher rates.